- Profile
Recreating Acoustics
The cultural heritage of a site is made up of more than its appearance; its soundscape is vital, as well. Acousticians and historians work together to preserve and recreate the auditory landscape of important sites through acoustical measurements and digital reconstructions based on architecture and building materials. Thanks to projects like these, researchers can achieve…
Aging Fluids
If you’ve ever left a sealed container of Playdoh untouched for months, you know that there’s a big difference between the fresh stuff and what’s left in that can. Aging can have big effects on non-Newtonian fluids. In this video, we see drops of a synthetic clay impacting at different speeds. In the top row…
Hammerhead Hydrodynamics
Hammerhead sharks have some of the most distinctive craniums in the ocean, which begs the question: how do they swim with that head? New computational fluid dynamics studies suggest that their long foil-shaped heads help the sharks maneuver swiftly, but they come at the cost of substantially higher drag. The researchers found that drag on…
Rolling Off a Duck’s Back
Ducks and other water fowl need protection from the elements. Fortunately for them, the structure of their feathers cleverly helps them shed water. As seen in this video, feathers have tiny hooks, called barbicels, that act like Velcro, zipping the individual barbs of a feather together to keep water out. When birds preen, they’re using…
Density Drift
This colorful photo shows three fluids — oil, water, and dish soap — illuminated by the rainbow reflection of a CD. The differing densities of each fluid creates a stratification with water sandwiched between dish soap on the bottom and oil on the top. Because the dish soap is miscible in water, it leaves a…
The Structure of the Blue Whirl
Several years ago, researchers discovered a new type of flame, the blue whirl. Now computational simulations have helped them untangle the complex structure of this clean-burning flame. Their work shows that the blue whirl is made up of three types of flames, which meet to form a fourth. The conical base of the whirl is…
The Greedy Cup in Your Washing Machine
A Pythagorean, or “greedy” cup, is one that automatically drains itself once filled to a certain level. In other words, it’s a self-starting siphon – one that triggers only at certain fill level. And chances are you have an example of this mechanism close at hand: inside your washing machine’s soap tray. That’s why the…
Wrinkles on Bubble Collapse
A viscous bubble wrinkles when it collapses, and scientists long assumed this behavior was caused by gravity. But a new experiment shows that the buckling is, instead, driven by surface tension. To test gravity’s influence on bubble collapse, the researchers popped bubbles in three orientations: the (normal) upright orientation (Images 1 and 2), upside-down (Image…
Curls Past the Canaries
When winds flow past a solitary peak, like an island in the ocean, they’re disrupted into a series of counter-rotating curls. That’s what we see here stretching to the southwest of Madeira Island. The official name for this flow is a von Karman vortex street, and it can be found anywhere from a soap film…
Precipitation
Chemistry and fluid dynamics often go hand-in-hand. Here chemical reactions produce visible precipitates as one chemical drops into the other. The shapes that form are distinctly fluid dynamical, with vortex rings, plumes, and instabilities all appearing. In many applications, chemical reactions and fluid dynamics are tied inextricably to one another because the rate of chemical…